Cyanide is a readily available poison which is extremely dangerous and often fatal when consumed in relatively small dosages. The presence of cyanide in foods is difficult to detect since it does not possess an easily noticeable odor or color. As a result, a consumer cannot personally detect or be warned of cyanide adulteration which has occurred in a food product.
Packaging devices have been provided which warn a consumer of potential tampering or adulteration of the packaged products. These systems generally involve a physical modification of the package such as the presence of a plastic seal which when broken indicates tampering. However, if the warning signal given by the package is overlooked by the consumer or circumvented by the tamperer such as by injection, the consumer would not detect adulteration.
Curcumin, also known as turmeric yellow, has been used as a food dye on foods having acid to neutral pH values. Curcumin is the main coloring matter in turmeric which is a dried and ground root of curcuma longa, a perennial herb native to China, India and South America. Curcumin has the chemical name 1,7-bis (4-hydroxy-3-methoxy phenyl) -1,6-heptadiene -3,5-dione and the following structure: ##STR1##
The kinetics of curcumin degradation in aqueous solution was studied by Tannesen and Karlsen in 1985. At pH greater than 7.5, curcumin molecules are extremely unstable with the solution color being an orange red. Below pH 7, curcumin solution is yellow. At pH 7.75, the half life of curcumin is 50 minutes. At pH 10.8, it is about one minute. Degradation products have been identified to be ferulic acid and feruloylmethane.
The photochemical stability was studied by the same scientists and published in 1986. The Curcumin degradation follows first order kinetics with the best stability in methanol (half life being 92.7 hours).
Sodium and potassium cyanide are commercially available and extremely poisonous compounds. When dissolved in water, the resulting aqueous solutions have a high alkalinity. The presence of less than 100 milligrams of sodium or potassium cyanide in food products neutral to sight acid pH will cause the food pH to be alkaline. Accordingly, it is desirable to utilize curcumin to indicate the presence of cyanide in food products.
It is therefore an object of the present invention to employ curcumin to detect and warn of the presence of cyanide in or on food, drug or like products by using curcumin as a cyanide indicator in the product packaging.